X-Git-Url: https://git.dogcows.com/gitweb?p=chaz%2Fyoink;a=blobdiff_plain;f=src%2FMoof%2FPlane.hh;h=5ec59eab28e1c6115f4923b92892de9fd5e9d572;hp=06e4abdce63f59398f961a531942d7b63ec667ea;hb=2d77fb5fb3480f522658f30af6addd5146530517;hpb=64e3c3202d2c1956759fb4da36ca329816c9369a

diff --git a/src/Moof/Plane.hh b/src/Moof/Plane.hh
index 06e4abd..5ec59ea 100644
--- a/src/Moof/Plane.hh
+++ b/src/Moof/Plane.hh
@@ -28,15 +28,16 @@
 
 #ifndef _MOOF_PLANE_HH_
 #define _MOOF_PLANE_HH_
-	
+
 #include <Moof/Math.hh>
+#include <Moof/Shape.hh>
 
 
 namespace Mf {
 
 
-class Aabb;
-class Sphere;
+template <int D> class Aabb;
+template <int D> class Sphere;
 
 
 /*
@@ -44,7 +45,7 @@ class Sphere;
  * is normal to the plane.
  */
 
-struct Plane
+struct Plane : public Shape<3>
 {
 	Vector3	normal;
 	Scalar	d;
@@ -65,8 +66,41 @@ struct Plane
 		d(scalar) {}
 
 
+	Scalar intersectRay(const Ray<3>& ray, Ray<3>::Intersection& intersection)
+	{
+		// solve: [(ray.point + t*ray.direction) dot normal] + d = 0
+
+		Scalar denominator = cml::dot(ray.direction, normal);
+
+		// check for parallel condition
+		if (denominator == SCALAR(0.0))
+		{
+			if (isEqual(cml::dot(ray.point, normal), -d))
+			{
+				// the ray lies on the plane
+				intersection.point = ray.point;
+				intersection.normal = normal;
+				return SCALAR(0.0);
+			}
+
+			// no solution
+			return SCALAR(-1.0);
+		}
+
+		Scalar t = (cml::dot(ray.point, normal) + d) / denominator;
+		if (t > SCALAR(0.0))
+		{
+			ray.solve(intersection.point, t);
+			intersection.normal = normal;
+		}
+
+		return t;
+	}
+
+
 	/* Causes the normal of the plane to become normalized.  The scalar may also
-	 * be changed to keep the equation true. */
+	 * be changed to keep the equation true.  Word to the wise: don't normalize
+	 * a plane if the normal is the zero vector. */
 	void normalize()
 	{
 		Scalar mag = normal.length();
@@ -92,8 +126,8 @@ struct Plane
 		else                        return POSITIVE;
 	}
 
-	Halfspace intersects(const Aabb& aabb) const;
-	Halfspace intersects(const Sphere& sphere) const;
+	Halfspace intersects(const Aabb<3>& aabb) const;
+	Halfspace intersects(const Sphere<3>& sphere) const;
 };